Now it's more common to try to get 'bad' platforms dehosted altogether (e.g. Parler/Gab), subreddits try to get their 'alternatives' banned, and any company/group that challenges a big group is going to be bought out or otherwise dealt with. (See: FB's gobbling of companies to try to keep people in their garden instead of letting people chose which gardens they enjoy.)
We used to have the opportunity to walk into the woods and make our own playground. Now people will follow you and attack you for that. THAT'S the problem. Also we're becoming really fond of demanding community loyalty. HN doesn't have this problem (which is one reason I show up), but on other social media sites, it can be, for instance, forbidden to link to/talk about certain other sites. For example, on Reddit, it's common to ban people for posting in the 'wrong' Reddits, and on Twitter finding out somebody participates somewhere 'bad' is practically open season.
I should be able to go on HN and /b/, provided I follow my host's rules. I should also be able to set up my OWN site and explicitly say it's because I disagree with - say - HN's moderation policies without worrying about the site being attacked.